FotoWeb uses MongoDB to store metadata about the assets in the FotoWare system. By default it uses a built in MongoDB instance running on the same instance as the FotoWeb server. However, FotoWeb can also be configured to connect to a MongoDB replica set, which offers redundancy and high-availability.
When using a MongoDB replica set you need to define the replica set name and the MongoDB hosts in the FotoWeb configuration. To do so, access the Operations Center in a web browser and go to the FotoWeb tab. Then choose Configuration | Open. Go to the Service Options tab and choose the Database node.
By default, FotoWeb is set up to connect to the MongoDB instance that came with the installer and runs on the local host. This is illustrated in the screenshot above. To change this to a replica set, choose the option to Connect to a MongoDB Replica set and enter the Replica set name. Then fill in the MongoDB hosts, using the Add host button to create additional entries.
IMPORTANT: When FotoWeb runs using its own bundled MongoDB instance, the MongoDB server MUST be set to localhost, not the server's actual hostname. Otherwise FotoWeb will assume that it has been configured to use an external MongoDB instance and is then no longer responsible for starting and stopping the MongoDB instance itself. More details on this here.